1
|
Yang J, He Q, Wang Y, Pan Z, Zhang G, Liang J, Su L, Wang A, Zeng C, Luo H, Liu L, Li J, Rao Q, Wang B, Wang H, Chen P. Gegen Qinlian Decoction ameliorates type 2 diabetes osteoporosis via IGFBP3/MAPK/NFATc1 signaling pathway based on cytokine antibody array. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 94:153810. [PMID: 34798519 DOI: 10.1016/j.phymed.2021.153810] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 10/09/2021] [Accepted: 10/17/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Osteoporosis affects more than half the patients with type 2 diabetes mellitus (T2DM). Up to data, there is no effective clinical practice in managing type 2 diabetes osteoporosis (T2DOP) because of its complex pathogenesis. Gegen Qinlian Decoction (GQD) has been used for the long-term management of T2DM. However, the underlying mechanism of GQD in the treatment of T2DOP remains unknown. PURPOSE To reveal the role of GQD in T2DOP and its potential therapeutic targets in the management of T2DOP. STUDY DESIGN The effect of GQD on T2DOP was observed in db/db mice in four groups: model group, GQD low-dose group (GQD-L), GQD high-dose group (GQD-H), and metformin (positive control) group. C57BL/6J mice were used as the negative control group. METHODS Quantitative phytochemical analysis of GQD was performed using high-performance liquid chromatography (HPLC). Micro-CT and hematoxylin-eosin (H&E) staining were used to evaluate bone histomorphometry. To screen for candidate targets of GQD, a cytokine antibody array was used, followed by bioinformatics analysis. Quantitative real-time PCR (qRT-PCR) and western blotting (WB) were used to determine expression levels. RESULTS The major active components of GQD were confirmed by HPLC. Micro-CT and H&E staining showed that bone mass was significantly increased in the GQD-H group compared with the model group. Antibody arrays revealed that the expression of insulin-like growth factor binding protein 3 (IGFBP3) was elevated in the GQD-H group. The MAPK pathway was identified using bioinformatics analysis. Additionally, the levels of osteoclastogenesis-related genes, including cathepsin K (Ctsk), acid phosphatase 5 (Acp5), matrix metallopeptidase 9 (Mmp9), and ATPase H+ transporting V0 subunit D2 (Atp6v0d2) were significantly decreased in the GQD-H group. Compared with the model group, high-dosage GQD inhibited phosphorylation of extracellular signal-regulated kinases (ERKs) and P38 mitogen-activated protein kinase (MAPK) and the expression of c-Fos and nuclear factor of activated T cells 1 (NFATc1). CONCLUSION GQD plays a protective role in T2DOP by upregulating IGFBP3 expression and downregulating the IGFBP3/MAPK/NFATc1 signaling pathway. IGFBP3 in serum may also be a novel biomarker in the treatment of T2DOP. Our current findings not only expand the application of GQD, but also provide a theoretical basis and guidance for T2DOP.
Collapse
Affiliation(s)
- Junzheng Yang
- First School of Clinical Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China; The Laboratory of Orthopaedics and Traumatology of Lingnan Medical Research Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Qi He
- First School of Clinical Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China; The Laboratory of Orthopaedics and Traumatology of Lingnan Medical Research Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Yunhan Wang
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Zhaofeng Pan
- First School of Clinical Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China; The Laboratory of Orthopaedics and Traumatology of Lingnan Medical Research Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Gangyu Zhang
- First School of Clinical Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China; The Laboratory of Orthopaedics and Traumatology of Lingnan Medical Research Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Jianming Liang
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Lijun Su
- First School of Clinical Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China; The Laboratory of Orthopaedics and Traumatology of Lingnan Medical Research Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Ailin Wang
- Second School of Clinical Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Chuning Zeng
- First School of Clinical Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China; The Laboratory of Orthopaedics and Traumatology of Lingnan Medical Research Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Haoran Luo
- First School of Clinical Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China; The Laboratory of Orthopaedics and Traumatology of Lingnan Medical Research Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Lingyun Liu
- College of Basic Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Jianliang Li
- First School of Clinical Medicine, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China; The Laboratory of Orthopaedics and Traumatology of Lingnan Medical Research Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Qiuhong Rao
- Department of Pharmacy, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China
| | - Baohua Wang
- Department of Endocrinology, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, 12 Jichang Road, Baiyun District, Guangzhou 510405, PR China.
| | - Haibin Wang
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, 16 Jichang Road, Baiyun District, Guangzhou, Guangdon 510405, PR China.
| | - Peng Chen
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, 16 Jichang Road, Baiyun District, Guangzhou, Guangdon 510405, PR China.
| |
Collapse
|
2
|
Niinuma T, Kai M, Kitajima H, Yamamoto E, Harada T, Maruyama R, Nobuoka T, Nishida T, Kanda T, Hasegawa T, Tokino T, Sugai T, Shinomura Y, Nakase H, Suzuki H. Downregulation of miR-186 is associated with metastatic recurrence of gastrointestinal stromal tumors. Oncol Lett 2017; 14:5703-5710. [PMID: 29113198 PMCID: PMC5661378 DOI: 10.3892/ol.2017.6911] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/03/2017] [Indexed: 01/14/2023] Open
Abstract
Although dysregulation of microRNAs (miRNAs/miRs) is a common feature of human malignancies, its involvement in gastrointestinal stromal tumors (GISTs) is not fully understood. The present study aimed to identify the miRNAs that perform a role in GIST metastasis. miRNA expression profiles from a series of 32 primary GISTs were analyzed using microarrays, and miR-186 was observed to be downregulated in tumors exhibiting metastatic recurrence. Reverse transcription-quantitative polymerase chain reaction analysis of an independent cohort of 100 primary GISTs revealed that low miR-186 expression is associated with metastatic recurrence and a poor prognosis. Inhibition of miR-186 in GIST-T1 cells promoted cell migration. Gene expression microarray analysis demonstrated that miR-186 inhibition upregulated a set of genes implicated in cancer metastasis, including insulin-like growth factor-binding protein 3, AKT serine/threonine kinase 2, hepatocyte growth factor receptor, CXC chemokine receptor 4 and epidermal growth factor-containing fibulin-like extracellular matrix protein 1. These results suggest that the downregulation of miR-186 is involved in the metastatic recurrence of GISTs, and that miR-186 levels could potentially be a predictive biomarker for clinical outcome.
Collapse
Affiliation(s)
- Takeshi Niinuma
- Department of Molecular Biology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Masahiro Kai
- Department of Molecular Biology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Hiroshi Kitajima
- Department of Molecular Biology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Eiichiro Yamamoto
- Department of Molecular Biology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan.,Department of Gastroenterology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Taku Harada
- Department of Molecular Biology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Reo Maruyama
- Department of Molecular Biology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Takayuki Nobuoka
- Department of Surgery, Surgical Oncology and Science, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Toshirou Nishida
- Department of Surgery, National Cancer Center Hospital, Tokyo 104-0045, Japan
| | - Tatsuo Kanda
- Department of Surgery, Sanjo General Hospital, Sanjo 955-0055, Japan
| | - Tadashi Hasegawa
- Department of Surgical Pathology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Takashi Tokino
- Medical Genome Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Tamotsu Sugai
- Department of Molecular Diagnostic Pathology, Iwate Medical University School of Medicine, Morioka 020-8505, Japan
| | | | - Hiroshi Nakase
- Department of Gastroenterology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Hiromu Suzuki
- Department of Molecular Biology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| |
Collapse
|
3
|
Pessetto ZY, Ma Y, Hirst JJ, von Mehren M, Weir SJ, Godwin AK. Drug repurposing identifies a synergistic combination therapy with imatinib mesylate for gastrointestinal stromal tumor. Mol Cancer Ther 2014; 13:2276-87. [PMID: 25122069 DOI: 10.1158/1535-7163.mct-14-0043] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Gastrointestinal stromal tumor (GIST) is a rare and therefore often neglected disease. Introduction of the kinase inhibitor imatinib mesylate radically improved the clinical response of patients with GIST; however, its effects are often short-lived, with GISTs demonstrating a median time-to-progression of approximately two years. Although many investigational drugs, approved first for other cancers, have been subsequently evaluated for the management of GIST, few have greatly affected the overall survival of patients with advanced disease. We employed a novel, focused, drug-repurposing effort for GIST, including imatinib mesylate-resistant GIST, evaluating a large library of FDA-approved drugs regardless of current indication. As a result of the drug-repurposing screen, we identified eight FDA-approved drugs, including fludarabine phosphate (F-AMP), that showed synergy with and/or overcame resistance to imatinib mesylate. F-AMP induces DNA damage, Annexin V, and caspase-3/7 activities as the cytotoxic effects on GIST cells, including imatinib mesylate-resistant GIST cells. F-AMP and imatinib mesylate combination treatment showed greater inhibition of GIST cell proliferation when compared with imatinib mesylate and F-AMP alone. Successful in vivo experiments confirmed the combination of imatinib mesylate with F-AMP enhanced the antitumor effects compared with imatinib mesylate alone. Our results identified F-AMP as a promising, repurposed drug therapy for the treatment of GISTs, with potential to be administered in combination with imatinib mesylate or for treatment of imatinib mesylate-refractory tumors.
Collapse
Affiliation(s)
- Ziyan Y Pessetto
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Yan Ma
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | - Jeff J Hirst
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas
| | | | - Scott J Weir
- Department of Pharmacology, Toxicology and Therapeutics, Kansas City, Kansas. Institute for Advancing Medical Innovation, University of Kansas Medical Center, Kansas City, Kansas. University of Kansas Cancer Center, Kansas City, Kansas
| | - Andrew K Godwin
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas. University of Kansas Cancer Center, Kansas City, Kansas.
| |
Collapse
|
4
|
Pessetto ZY, Weir SJ, Sethi G, Broward MA, Godwin AK. Drug repurposing for gastrointestinal stromal tumor. Mol Cancer Ther 2013; 12:1299-309. [PMID: 23657945 DOI: 10.1158/1535-7163.mct-12-0968] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Despite significant treatment advances over the past decade, metastatic gastrointestinal stromal tumor (GIST) remains largely incurable. Rare diseases, such as GIST, individually affect small groups of patients but collectively are estimated to affect 25 to 30 million people in the United States alone. Given the costs associated with the discovery, development, and registration of new drugs, orphan diseases such as GIST are often not pursued by mainstream pharmaceutical companies. As a result, "drug repurposing" or "repositioning," has emerged as an alternative to the traditional drug development process. In this study, we screened 796 U.S. Food and Drug Administration (FDA)-approved drugs and found that two of these compounds, auranofin (Ridaura) and fludarabine phosphate, effectively and selectively inhibited the proliferation of GISTs, including imatinib-resistant cells. One of the most notable drug hits, auranofin, an oral, gold-containing agent approved by the FDA in 1985 for the treatment of rheumatoid arthritis, was found to inhibit thioredoxin reductase activity and induce reactive oxygen species (ROS) production, leading to dramatic inhibition of GIST cell growth and viability. Importantly, the anticancer activity associated with auranofin was independent of imatinib-resistant status, but was closely related to the endogenous and inducible levels of ROS. Coupled with the fact that auranofin has an established safety profile in patients, these findings suggest for the first time that auranofin may have clinical benefit for patients with GIST, particularly in those suffering from imatinib-resistant and recurrent forms of this disease.
Collapse
Affiliation(s)
- Ziyan Y Pessetto
- Department of Pathology & Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | | | | | | | | |
Collapse
|
5
|
Rink L, Ochs MF, Zhou Y, von Mehren M, Godwin AK. ZNF-mediated resistance to imatinib mesylate in gastrointestinal stromal tumor. PLoS One 2013; 8:e54477. [PMID: 23372733 PMCID: PMC3556080 DOI: 10.1371/journal.pone.0054477] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 12/12/2012] [Indexed: 12/14/2022] Open
Abstract
Although imatinib mesylate (IM) has transformed the treatment of gastrointestinal stromal tumors (GIST), many patients experience primary/secondary drug resistance. In a previous study, we identified a gene signature, consisting mainly of Kruppel-associated box (KRAB) domain containing zinc finger (ZNF) transcriptional repressors that predict short-term response to IM. To determine if these genes have functional significance, a siRNA library targeting these genes was constructed and applied to GIST cells in vitro. These screens identified seventeen “IM sensitizing genes” in GIST cells (sensitization index (SI) <0.85 ratio of drug/vehicle) with a false discovery rate (FDR) <15%, including twelve ZNF genes, the majority of which are located within the HSA19p12–13.1 locus. These genes were shown to be highly specific to IM and another tyrosine kinase inhibitor (TKI), sunitinib, in GIST cells. In order to determine mechanistically how these ZNFs might be modulating response to IM, RNAi approaches were used to individually silence genes within the predictive signature in GIST cells and expression profiling was performed. Knockdown of the 14 IM-sensitizing genes (10 ZNFs) universally led to downregulation of six genes, including TGFb3, periostin, and NEDD9. These studies implicate a role of KRAB-ZNFs in modulating response to TKIs in GIST.
Collapse
Affiliation(s)
- Lori Rink
- Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, United States of America.
| | | | | | | | | |
Collapse
|
6
|
Italiano A, Chen J, Zhang L, Hajdu M, Singer S, DeMatteo RP, Antonescu CR. Patterns of deregulation of insulin growth factor signalling pathway in paediatric and adult gastrointestinal stromal tumours. Eur J Cancer 2012; 48:3215-22. [PMID: 22770876 DOI: 10.1016/j.ejca.2012.05.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 05/11/2012] [Accepted: 05/22/2012] [Indexed: 12/17/2022]
Abstract
BACKGROUND Data regarding the patterns and the mechanisms of deregulation of the insulin growth factor (IGF) pathway in adult and paediatric gastrointestinal stromal tumours (GISTs) are limited. METHODS We investigated the expression profiling of the genes encoding the main components of the IGF signalling pathway in 131 GISTs (106 adults, 21 paediatric and four young adults) and 25 other soft-tissue sarcomas (STS) using an Affymetrix U133A platform. IGF2 was investigated for loss of imprinting (LOI) whereas IGF1R was analysed for copy number aberration and mutation. RESULTS IGF2 was the most highly overexpressed gene of the IGF pathway in GIST. IGF2 expression was also significantly higher than in other STS. IGF2 expression was correlated to the age onset and mutational status of GIST. Indeed, IGF2 expression was significantly higher in the 'adult' group than in the 'paediatric' and 'young adult' groups. Among adult GIST, IGF2 expression was higher in tumours lacking Homo sapiens v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) or alpha-type platelet-derived growth factor receptor (PDGFRA) mutations in comparison with mutated cases. A trend for a higher expression of IGF2 in resistant GIST in comparison to responsive GIST was also found. Overexpression of IGF2 was not related to LOI. Conversely, the expression of the IGF1R gene was significantly higher in the paediatric group than in the adult group. No copy number gains or mutations of IGF1R were observed. CONCLUSION The IGF pathway is deregulated in GIST with distinct patterns according to age onset and mutational status. The IGF pathway may represent a therapeutic target in patients with primary or secondary resistance to imatinib.
Collapse
Affiliation(s)
- Antoine Italiano
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
| | | | | | | | | | | | | |
Collapse
|
7
|
Kulkarni A, Thota B, Srividya MR, Thennarasu K, Arivazhagan A, Santosh V, Chandramouli BA. Expression pattern and prognostic significance of IGFBP isoforms in anaplastic astrocytoma. Pathol Oncol Res 2012; 18:961-7. [PMID: 22547392 DOI: 10.1007/s12253-012-9526-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 03/27/2012] [Indexed: 11/28/2022]
Abstract
The role of insulin-like growth factors and their regulatory proteins (IGFBP isoforms) in gliomas, particularly glioblastoma, has been a subject of active research in recent years. There is paucity of literature on their expression and impact on clinical outcome in anaplastic astrocytomas. To evaluate the expression patterns of IGFBP isoforms in anaplastic astrocytoma and correlate with clinical outcome, a retrospective study of 53 adult patients operated for supratentorial lobar anaplastic astrocytoma was performed. The protein expression of IGFBP isoforms (IGFBP-2, -3, -5 and -7), was studied by immunohistochemistry on all samples. The patients were followed up and outcome was documented. The median age at presentation in the present study was 35 years. The pattern of staining was intra cytoplasmic, homogenous and diffuse for IGFBP-2, -3 and -5 and granular for IGFBP-7. IGFBP-2 expression was significantly low in anaplastic astrocytoma as compared to other isoforms (P < 0.001). IGFBP-3 expression was higher than the other isoforms. However, its' expression correlated with favorable overall survival and demonstrated a trend towards significance on univariate analysis. The present study is the first of its kind to describe comprehensively the pattern of expression of IGFBP isoforms (IGFBP-2, -3, -5 and -7) in anaplastic astrocytomas. IGFBP-2 and IGFBP-3 expression patterns and correlation to prognosis were distinct in anaplastic astrocytoma patients, contradictory to what has been reported in glioblastoma, thus giving further evidence that anaplastic astrocytomas are molecularly distinct from glioblastoma.
Collapse
Affiliation(s)
- A Kulkarni
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India
| | | | | | | | | | | | | |
Collapse
|
8
|
Synergistic induction of apoptosis by the Bcl-2 inhibitor ABT-737 and imatinib mesylate in gastrointestinal stromal tumor cells. Mol Oncol 2010; 5:93-104. [PMID: 21115411 DOI: 10.1016/j.molonc.2010.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/07/2010] [Accepted: 10/08/2010] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Although imatinib mesylate has revolutionized the management of patients with gastrointestinal stromal tumor (GIST), resistance and progression almost inevitably develop with long-term monotherapy. To enhance imatinib-induced cytotoxicity and overcome imatinib-resistance in GIST cells, we examined the antitumor effects of the pro-apoptotic Bcl-2/Bcl-x(L) inhibitor ABT-737, alone and in combination with imatinib. METHODS We treated imatinib-sensitive, GIST-T1 and GIST882, and imatinib-resistant cells with ABT-737 alone and with imatinib. We determined the anti-proliferative and apoptotic effects by cell viability assay, flow cytometric apoptosis and cell cycle analysis, immunoblotting, and nuclear morphology. Synergism was determined by isobologram analysis. RESULTS The IC(50) of single-agent ABT-737 at 72 h was 10 μM in imatinib-sensitive GIST-T1 and GIST882 cells, and 1 μM in imatinib-resistant GIST48IM cells. ABT-737 and imatinib combined synergistically in a time- and dose-dependent manner to inhibit the proliferation and induce apoptosis of all GIST cells, as evidenced by cell viability and apoptosis assays, caspase activation, PARP cleavage, and morphologic changes. Isobologram analyses revealed strongly synergistic drug interactions, with combination indices <0.5 for most ABT-737/imatinib combinations. Thus, clinically relevant in vitro concentrations of ABT-737 have single-agent antitumor activity and are synergistic in combination with imatinib. CONCLUSION We provide the first preclinical evidence that Bcl-2/Bcl-x(L) inhibition with ABT-737 synergistically enhances imatinib-induced cytotoxicity via apoptosis, and that direct engagement of apoptotic cell death may be an effective approach to circumvent imatinib-resistance in GIST.
Collapse
|